1. Field of the Invention
The present invention relates to a transmission power control apparatus in an earth station for satellite communication.
In satellite communication, a plurality of earth stations will transmit and receive signals via a single satellite. Therefore the transmission power from the earth stations must be strictly managed so as not to seriously disturb the other communication channels.
Also, satellite communication is carried out through space transmission paths, therefore it is different from optical fiber communication etc. The channel quality thereof is conspicuously affected by weather conditions between the satellite and the earth stations. For this reason, the transmission power from the earth stations must be controlled according to the changes in the weather conditions.
The present invention refers to a transmission power control apparatus for performing the control of the transmission power.
2. Description of the Related Art
As will be explained in detail below by referring to the drawings, in general, a satellite communication earth station (hereinafter also simply referred to as an earth station) incorporates a transmission power control apparatus. This control apparatus is connected to external apparatuses such as an antenna via a reception system and a transmission system. Also, this control apparatus includes a reception characteristic detection unit for the received signal obtained from the reception system, for example, a beacon signal. The transmission power level in the transmission system is variably controlled according to the output from this detection unit.
The transmission power control apparatus having a conventional configuration mentioned above merely feeds back the characteristic of the received signal at the reception system, detected by the reception characteristic detection unit, to the transmission system as it is and suffers from a problem that it cannot meet demands for maintaining a further higher grade of channel quality.